4/18/2007

The arrows represent the movement of the H5N1 virus into the three distinct regions represented in the genome study. The green, pink and yellow arrows depict the three strains of avian flu that have emerged independently in the West. The orange arrows show the likely source of all the avian influenza strains, which is in China. From there it has moved south into Vietnam and west into central Asia and Russia.

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VIRUS ALERTBIRD-FLU IS SPREADINGApril 16, 2007

Newswise — In a paper in the May issue of Emerging Infectious Diseases, an international team of researchers report the first ever large-scale sequencing of western genomes of the deadly avian influenza virus, H5N1.

Their study of 36 genomes of the virus collected from wild birds in Europe, the Middle East and Africa (EMA), and Vietnam confirms not only that the virus has very recently spread west from Asia, but that two of the new western strains have already independently combined, or “reassorted,” to create a new strain.

Several samples also contained the mutation associated with the form of the “bird flu” that caused several human deaths in 2006. It is the virus’s ability to rapidly mutate into a pathogen that may eventually be passed between humans that concerns health officials about a worldwide pandemic of H5N1 influenza.

The study also produced some evidence that strengthens the case that humans have had an impact on the movement of the flu out of Asia.

“This is the first time anyone’s looked at all of the H5N1 genomes in the west,” said Steven Salzberg, the study’s lead author and director of the University of Maryland Center for Bioinformatics and Computational Biology. “Until now, the studies have been primarily on samples from the Far East. Our study shows that the virus is spreading west, and that there have been three separate introductions of H5N1 in Europe, the Middle East and Africa.”

Emerging Infectious Diseases is a journal of the Centers for Disease Control and Prevention.